Heretofore there is known an image pickup device constructed by mounting an image pickup element on an image pickup element mounting substrate. As an example of the image pickup element mounting substrate for use in such an image pickup device, there is one comprising a frame body composed of insulating layers, and a flat plate joined to a lower surface of the frame body. In such an image pickup element mounting substrate, an external circuit connection electrode is disposed on an upper surface or side surface of the frame body for connection with an external circuit.
The recent demand for further and further miniaturization in image pickup devices has led to difficulties in leaving a space for the mounting of an external circuit connection electrode and an electronic component on the upper surface of the frame body. With this in view, for example, Japanese Unexamined Patent Publication JP-A 2006-129255 discloses techniques for mounting an electronic component on the lower surface of the frame body, so that the upper surface or side surface of the frame body may be connected with an external circuit.
However, due to variations in accuracy of dimension in an electronic component in itself, variations in accuracy of position and in accuracy of dimension resulting from the production of a pad for the connection of the electronic component, and variations in accuracy of mounting position in the course of mounting of the electronic component, it has been difficult to render the lower surfaces of a plurality of electronic components flush with each other after the mounting. Consequently, the level of the inside of the image pickup element mounting substrate could vary from place to place. This causes the image pickup device to be inclined when mounted in an external circuit or external housing, in consequence whereof there results misalignment in optical axis or image noise as a matter of concern.
An object of the invention is to provide an image pickup element mounting substrate capable of reducing an inclination of an image pickup device caused by placement of an electronic component, and an image pickup device which employs this image pickup element mounting substrate.